Expert Analysis

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Continuous positive airway pressure (CPAP) therapy is the most common treatment used across the spectrum of obstructive sleep apnea (OSA) severity, and is the recommended initial treatment for most patients with moderate to severe OSA. CPAP has been demonstrated to consistently improve symptoms of daytime sleepiness in those with moderate to severe disease and may improve blood pressure and other cardiovascular outcomes in patients who are consistently compliant with therapy.

Despite its effectiveness in resolving sleep disordered breathing, adherence to CPAP therapy is approximately 50%. Interventions demonstrated to improve initial CPAP use include education, heated humidification and cognitive behavioral therapy added to education. Advanced technology PAP devices, such as autoPAP (APAP) and bilevel therapies, have not been shown to consistently improve adherence in patients who are CPAP naïve or in patients who have been intolerant to standard CPAP therapy. While various approaches to treatment and advancements in technology have evolved to improve adherence, compliance with CPAP therapy has remained relatively unchanged over time.

Despite the less than optimal adherence to CPAP therapy, most studies evaluating methods to improve CPAP adherence have been focused on patients that are newly initiated to CPAP therapy. There have been relatively few studies evaluating interventions to improve CPAP compliance in patients who are having difficulty with, or are intolerant to, CPAP therapy. Clinical experience and data from clinical trials demonstrate that clinicians should address common problems such as poor mask fit, excessive leak, adjustments in humidification, and assuring proper treatment settings prior to discontinuing CPAP therapy. Most of the available PAP compliance software provides useful data that can help clinicians troubleshoot these problems to improve outcomes. Treatment options for OSA patients requiring treatment, but who are unable or unwilling to tolerate CPAP therapy, include weight loss, oral appliances, and upper airway surgeries. Alternative approaches that have come to the market more recently, including nasal expiratory resistance and oral negative pressure devices, will also be discussed.

Weight loss: OSA is associated with obesity and an elevated body mass index (BMI) is an independent risk factor for OSA in patients under the age of 60. Several studies have demonstrated that dietary weight loss is associated with significant improvements in OSA as measured by reductions in the apnea-hypopnea index (AHI)1. Unfortunately, as would be expected, most studies show that patients typically achieve only modest reductions in weight with diet and behavioral counseling with clinically significant residual OSA persisting in most patients. Surgical weight loss via various bariatric procedures has been associated with even greater reductions in weight as well as improvements in OSA. In general, there is a dose dependent improvement in OSA for a given amount of weight loss, though most patients, regardless of the method of weight loss, have residual OSA despite significant reductions in weight. A recent randomized controlled trial showed that while bariatric surgery resulted in weight loss that was significantly greater than diet with counseling over a 2 year period, the reductions in AHI were not statistically different between the two groups2.

In summary, while significant weight loss can lead to improvements in OSA, the data demonstrate that the majority of patients do not achieve or maintain enough weight loss to resolve their sleep disordered breathing and thus will require ongoing treatment for the OSA. Given these data, weight loss should not be considered a primary therapy for moderate to severe OSA and should be recommended as a secondary therapy or intervention that supplements a primary treatment such as CPAP or oral appliances. Further, even for those patients who are able to lose a significant amount of weight and maintain that weight loss over time, a follow up sleep study should be performed to assess for residual disease prior to discontinuing CPAP therapy.

Oral appliances: Oral appliances are dental devices that improve sleep disordered breathing by maintaining the patency of the posterior pharynx. These devices are typically fit by a dentist and maintain pharyngeal patency by advancing the mandible forward and or by maintaining the tongue in an anterior position. They are indicated for patients with mild to moderate OSA and for patients with severe OSA who are intolerant or choose not to use CPAP therapy3. In addition to less severe disease, other predictors of a more favorable response to oral appliance therapy include younger age, lower BMI, smaller neck circumference and those with more positional (supine dependent) OSA.

In general, CPAP is more effective at resolving sleep disordered breathing and improving oxygen saturations, though oral appliances tend to improve symptoms of daytime sleepiness to similar degree as CPAP. The effect of oral appliances on improving cardiovascular outcomes such as hypertension is not clear at this time. A recent meta-analysis that reviewed 7 studies demonstrated a favorable effect on many parameters of blood pressure, though most of the data were derived from observational studies4. Thus more randomized controlled data with longer follow up are required prior to drawing definite conclusions. The impact of oral appliance therapy on other cardiovascular outcomes such as arrhythmias and mortality are unknown.

Commercial insurance companies and Medicare typically reimburse for oral appliance therapy, though commercial reimbursement varies by region. Oral appliances should be fit and titrated by dentists that are trained in the management of OSA. After an initial titration period, patients should undergo either polysomnography or out-of-center portable testing to objectively confirm the efficacy of the device.

Positional therapy: Some patients with OSA, only have significant sleep disordered breathing in the supine position. Thus, some clinicians may prescribe positional therapy to patients with less severe disease whose OSA occurs predominantly in the supine position. This treatment may be achieved though various interventions, such as tennis ball placed in the back of a nightshirt or through more formal devices that have been developed specifically for this purpose. Most studies evaluating the effectiveness of positional therapy are based on data from small, uncontrolled studies with relatively short-term follow up. A few observational trials with longer-term follow suggest that compliance with positional therapy over time is poor. Thus, positional therapy using various modalities should typically be recommended for patients as a secondary or supplemental therapy.

Miscellaneous devices: Other devices have recently been developed as alternative treatments for patients who are unable or to unwilling to use CPAP therapy5,6. Nasal expiratory resistive devices (Provent® by Theravent Inc) are disposable adhesive devices placed over the nostrils. These devices increase resistance during exhalation thereby increasing upper airway patency by maintaining positive pressure in the upper airway prior to inhalation when the upper airway is most likely to collapse. Randomized controlled data demonstrate that this treatment can improve OSA, though best results are typically observed in patients with more mild disease. In practice, these devices have experienced limited use as they are difficult for many patients to use, insurance coverage is poor and objective documentation of efficacy is difficult to determine using conventional technology.

Another therapy recently introduced is an oral negative pressure device (Winx® by Apnicure Inc). This deceive creates negative oral pressure keeping the tongue and soft palate in more anterior positions. A recent short-term randomized controlled trial demonstrated that the device is well tolerated and results in improved OSA in patients with mild to severe OSA. While OSA was improved, most patients demonstrated residual mild to moderate OSA. The role of this technology in the treatment of OSA is yet to be determined.

Surgery and medications: Various surgical approaches have been used to treat or improve OSA. In general, these approaches should be considered only after a trial of CPAP and or oral appliance therapy has been unsuccessful7. This topic is covered in more detail in a separate article by Dr. Caples. There are currently no medications that are recommended or approved as primary or supplemental therapies in patients who are intolerant or unwilling use CPAP therapy.

Summary: When patients with OSA are unwilling or unable to tolerate CPAP therapy, the following options should be considered:

First, evaluate the patient for proper mask fit, excessive leak and proper pressure settings. Current compliance software can aid in this evaluation. Education focused on proper CPAP use, in addition to these interventions, has been shown to improve CPAP adherence in patients who have previously been CPAP intolerant.

Consider weight loss, either though diet or bariatric procedures for obese patients. Most patients will require other therapy in addition to weight loss, as most patients will have clinically significant residual OSA despite substantial weight loss. Thus, follow up objective testing is recommended after significant weight loss is achieved to objectively determine the need for ongoing therapy.

Oral appliances are reasonable alternatives to CPAP therapy, especially in patients with mild to moderate disease. A trained dentist should fit and adjust the device and objective testing after device titration is recommended to document treatment efficacy.

Upper airway surgery can be considered for patients who cannot tolerate CPAP or oral appliance therapy. Current data evaluating various procedures are limited and more information is required to determine which procedures may benefit certain patient groups.

Newer interventions such as nasal expiratory resistive and oral negative pressure devices may offer alternatives for some patients. These devices tend to work better in patients with less severe disease, and significant residual sleep disordered breathing should be expected in many patients. Long-term data is not available for either one of these interventions.